1. Field of the Invention
The present invention relates generally to a remote control receiver which receives a remote control signal from a remote control which is used in a game machine, etc.
2. Description of Related Art
In a conventional game machine, a game machine body receives signals from a remote control on radio waves or infrared rays. It is convenient because a person can operate the remote control anywhere from the body of the game machine.
The above-mentioned remote control generates a remote control signal by serially arranging data in a plurality of bits, one-bit data being defined by the presence of a pulse with predetermined width. A transmitted waveform defines a pulse with use of a carrier. For instance, when the carrier is transmitted, the pulse is defined as a low level (L-level), and when the carrier is not transmitted, the pulse is defined as a high level (H-level). At the receiving side, the pulse is defined as the L-level or the H-level in the same manner.
The distance between the game machine body and the remote control varies in the transmission of the data from the remote control to the game machine body. The intensity of the signal, which the game machine body receives, varies according to the distance. For this reason, there is a disadvantage in that the data cannot be read correctly since a received waveform in the game machine body varies according to the transmission distance.
Specifically, if the remote control is close to the game machine body, or if the transmission distance is short, the pulse width of a received signal, which is reproduced by the game machine body, is larger than the pulse width of a transmitted signal, which is output from the remote control. If the remote control is far from the game machine body, or if the transmission distance is long, the pulse width of a received signal, which is reproduced by the game machine body, is smaller than the pulse width of a transmitted signal from the remote control.
The pulse width of the transmitted signal, which is output from an ordinarily remote control, is between 500 .mu.s and 600 .mu.s. No trouble occurs in the reception if the pulse width changes only within the range of between .+-.200 .mu.s and .+-.250 .mu.s. In the case of a high-speed communication which transmits the data ten times faster than a conventional communication, a change in pulse width must be within the range of .+-.20 .mu.s.
Since the pulse width of the transmitted signal varies according to the transmission distance as stated above, the remote control can only be used within the transmission distance of between 1 m and 2.5 m in the high-speed communication wherein the change in pulse width is restricted within the range of .+-.20 .mu.s, compared with an ordinary communication wherein the remote control which can be used within the transmission distance of between 0.2 m and 8 m. For this reason, the remote control is not practical.